Spin switch

ABSTRACT

THIS INVENTION RELATES TO A NORMALLY CLOSED, DOUBLE POLE, DOUBLE THROW SPIN ACTUATED ELECTRICAL SWITCH FOR SAFING AND ARMING A MISSILE. THE DEVICE USES A SEALED HOUSING MEANS, A TERMINAL MEANS OPERATIVELY SEALED WITHIN SAID HOUSING HAVING A PAIR OF NORMALLY OPENED CONTACTS AND A PAIR OF NORMALLY CLOSED CONTACTS, A PISTON POLE MEANS SLIDABLY POSITIONED AND BIASEDLY HELD WITHIN THE HOUSING AND RESPONSIVE TO THE CENTRIFIGAL FORCES CREATED BY THE SPIN OF THE LAUNCHED MISSILE CARRIER, THE SPIN FORCE CLOSES THE NORMALLY OPEN CONTACT AND OPENS NORMALLY CLOSED CONTACTS.

w. PELLET 3,705,965

sPIN SWITCH Filed sept. 10. 1971 wdlmj, MM Q33: z; www@ United States Patent O 3,705,965 SPIN SWITCH William Pellet, Succasunna, NJ., assigner to the United States of America as represented by the Secretary of the Army Filed Sept. 10, 1971, Ser. No. 179,369 Int. Cl. H0111 35/14 U.S. Cl. 20061.53 2 Claims ABSTRACT OF THE DISCLOSURE 'Ihe invention :described herein may tbe manufactured, used and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

BACKGROUND OfF THE INVENTION Various safety means to protect launch crews have been used in missile and projectile launchings to prevent inadvertent arming and malfunction either prior to or during the launching period. Some of these prior art devices have used electrical switches actuated by the missiles accelerating forces to provide the energy necessary to effect an electrical discontinuity. These prior art devices have sutered from a combination of disadvantages which include large size, inability to withstand large transverse g loads in excess of 15,000 gs, Icomplex mechanical switching mechanisms, fragility, heavy weight, high cost, limited storage life, low operational reliability, and deterioration due to exposure to the environment.

The present device is an electrical spin switch which is not only capable of reliably performing a switching function dependent upon prior angular accelerating velocities, but also can be made small in size, simple and rugged in construction, at low cost, resistant to environmental oxidation of switch contacts, and have good storage life.

SUMMARY OF THE INVENTION The present invention is an electrical switch which is designed to be utilized in a carrier which will spin after leaving the vicinity of the launching vehicle. The switch construction is such that it will perform its switching function only after the carrier to which it has been attached will reach a given angular velocity. In the present invention a slidable piston type pole means is held by a biased spring means in a housing in a rst-switching position. This rst switching position closes an upper set of electrical contacts or terminals. After the carrier is launchedand has attained a certain angular velocity the biased spring is compressed by the centrifugal g forces acting on the slidable pole means permitting the slidable pole means to move from the first switching position to a second switching position. In this second switch position a pair of normally opened terminals are closed by a pair of liexible contacts slidably positioned intermediate to the piston pole means and the contact containing body housing. The unique arrangement of the flexible and stationary contact surfaces permits the switch to be made in a very small size. The present device has been made as small as a three-eighths of an inch cube. This small size allows the minimal space available in a missile to be used for increasing the explosive charge and/or adding additional circuitry. Since the switching mechanism of the present invention is a simple modified piston contained within a cylinder it is inherently less complex than prior art devices containing the same number of switch contacts. Prior art devices which contain pinioned levers as the movable pole means are less resistant to transverse loading. The use of relatively large simple parts in the spin switch insures a more rugged switch. The weight of the spin switch is minimal due to the small size and the use of light weight insulating materials such as Lexan for the piston pole means and the main body housing. The present device has all moving parts sealed within the main body housing in order to minimize the environmental oxidation effects on the switch contact surfaces. In addition all metal terminal and contact elements are gold plated to resist oxidation which may occur on shelf life or in operation.

One of the objects of this invention is to provide a spin switch which is capable of withstanding g loads in excess of 15,000 gs.

Another object is to provide a spin switch which can withstand centrifugal g loads in excess of 15,000 gs and whose volume is less than 0.141 cubic inch.

Another object is to provide a spin switch which has all movable parts sealed within a housing.

Another object is to provide a spin switch Whose contact surface is resistant to environmental oxidation.

Another object is to provide a spin switch of rugged construction having a structurally simple piston type mechanical switching mechanism.

For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a top plan view of the spin switch.

FIG. 2 is a cross-sectional view of the illustration shown in FIG. 1 taken along line 2 2.

FIG. 3 is a cross-sectional view of the illustration shown in FIG. l taken along line 3-3.

FIG. 4 is a cross-sectional view of the illustration shown in FIG. 3 taken along line 4 4.

FIG. 5 is a cross-sectional view of the illustration shown in FIG. 3 taken along line 5-5.

Throughout the following description like reference numerals are used to denote like parts in the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 through 5 a cover 10y seals a cup-shaped insulator body housing 20 which has an axial cylindrical cavity 21 therein. The bottom surface 25 of the cylindrical cavity 21 has a spring positioning cylindrical shaped boss 22 projecting toward the cover 10. The housing 20 has molded therein and partially protruding therethrough a rst pair of arrow shaped lower stationary conducting terminals and contact surfaces 40 and 41 and a second pair of arrow shaped lower stationary conducting terminals and contacts 42 and 43. Housing 20 has a pair of semi-circular upper stationary terminals and contacts S0 and 51 molded in a plane above the lower stationary contacts and parallel to a plane containing 40, 41, 42 and 43, and also has terminal ends partially protruding through the housing 20. The lower stationary conducting terminals 40, 41, 42, 43 and the upper stationary conducting terminals 50, 51, lay in planes which are parallel to each other and transverse to the longitudinal axis of the cylindrical cavity 21.

A cylindrical piston pole means 30 slidably ts into the cylindrical cavity 21. Piston 30 has an axially aligned air passage 31 which is intermediate to piston top surface 32 and a spring positioning piston bore 33. This passage 31 permits the gas intermediate to the body 20 and the piston 30 to flow toward the space vacated by the piston 30 in its travel thereby permitting the gas pressure to equalize. A pair of semi-circular longitudinal piston grooves 34, 35 are diametric to each other and opposite from a matching pair of semi-circular longitudinal body grooves 23 and 24 which are likewise diametrically positioned in the body housing 20 so that when a pair of anti-rotation pins 70 and 71 are positioned within the longitudinal bores formed by the longitudinal piston grooves 34, 35 and the matching body grooves 23, 24 the piston 30 will be free to move within the cylindrical cavity 21 in a longitudinal direction but will be restrained from rotational movement. Piston 30 has a pair of diametrically positioned transverse flexible contact grooves 36 and 37 which provide space for retaining and posttioning therein flexible contacts 60 and 61 respectively. One end of the helical coil spring 80 is operatively positioned over the cylindrical boss 22 and the other end is positioned within the spring positioning piston bore 3'3 so as to biasedly hold the piston pole means 30 in the pre-launch position shown in FIGS. 2 and 3. In the prelaunch position, the switch and the carrier to which it is attached are not being subjected to the centrifugal forces of spin.

In operation, the spin switch is mounted in the projectile carrier with the cover and the longitudinal axis of the piston pointed transverse the direction of the carriers axis of rotation. When the carrier is in a prelaunch condition the compressive force of the helical coil spring 80 will maintain the pole means 30 so that the upper stationary pair of terminals 50, 51 will be normally closed by the flexible contact 60, 61. Under this switching condition the electrical functions that should not occur until after launch would be prevented from occurring by the discontinuity of the electrical path between any circuit connected to the first pair of lower stationary terminals 40, 41 and between any circuit connected to the second pair of lower stationary terminals 42, 43. In like mannner any electrical function which required closure of a circuit or shorting of a portion of a circuit for sang conditions would be affected by the normally closed position of the pair of upper stationary terminals 50, 51 by the pole means 30 position as shown in FIGS. 2, 3 and 4.

After the carrier is launched the centrifugal forces acting on the piston pole means 30 will compress the helical spring 80, carrying the flexible contacts 60, 61 from the normally closed junction between the upper stationary terminals 50, 51 to the normally open rst and second pair of lower stationary terminals 40, 41 and 42, and 43 respectively. At this point in the sequence of operation the spin switch having been subjected to sustained angular velocity will have closed two normally open paths of electrical continuity and opened one normally closed electrical circuit. The present inventions method of incorporating llexible contacts 60, 61 within the pole means is particularly advantageous because it allows more electrical contacts to be made in a smaller volume than heretofore possible. The sealed construction of the spin switch minimizes the possibility of environmental contaminates effecting the switch contact resistivity thereby improving reliability and shelf life.

From the above description, it will be evident the invention provides a normally closed double pole double throw spin switch which can reliably perform electrical safng and arming functions in missile and projectile applications under high centrifugal loading conditions in a very small volume.

I wish it to be understood that I do not desire to be limited to the exact detail of construction shown and described for obvious modifications will occur to a person skilled in the art.

What is claimed is: e

1. A normally closed, double pole, double throw actuated electrical switch for safng and arming a missile carrier comprising:

a housing means which includes;

a cup-shaped insulator having an axial cylindrical cavity therein, a concentric cylindrical shaped boss protruding into said cavity, an internal longitudinal body groove; a cover hermetically sealing said cup-shaped insulator.

terminal means within said housing means and extending out thereof having a first and second normally opened pair of lower contacts and a pair of normally closed upper contacts;

piston pole means slidably positioned within said housing which includes;

a cylindrical insulator having on one end a top surface and on the other end a concentric spring positioning piston bore, and an air passage intermediate to said top surface and said spring positioning bore; a longitudinal piston groove positioned from said internal longitudinal body housing groove; a pair of diametrically positioned transverse grooves; a conducting flexible contact positioned within each of said transverse grooves, opens said normally closed upper contacts after the carrier vehicle is launched and closes said first and second pair of normally opened lower contacts upon sliding motion of said piston;

a helical spring holding said piston pole means and said housing in a position which shorts said normally closed contacts and opens said normally open contacts; and

an anti-rotational means operatively positioned intermediate to said piston means and said housing means prevents said piston means from rotating within said housmg and permits said piston means to slidably move in a direction parallel to the longitudinal axis of the piston means.

2. A switch as recited in claim 1 wherein said antirotational means comprises a pin located within said internal longitudinal piston groove and said adjacent internal longitudinal body housing grooves thereby preventing said piston pole means from rotating in said housing and permitting said piston means to slidably respond to said carrier spin forces.

References Cited UNITED STATES PATENTS 2,634,400 4/ 1953 Sweet 20G-80 R HERMAN J. HOHAUSER, Primary Examiner U.S. Cl. X.R. 200-- 

